1. Field of the Invention
The invention relates to machines for making pancakes or any other edible or non-edible products obtained by baking or heating a paste spread in small thickness over a given configuration.
2. Description of the Prior Art
For the industrial manufacture of such products, of tasting pancakes for example, numerous machines have been conceived. All include a heating surface and a spreading device designed to transfer the paste from a container to the heating surface.
The heating or baking surface is theoretically of any type but generally it is flat or developable and it is in relative movement with respect to the spreader. Mostly it is continuous and constituted for example by a rotating plate, an endless heating band, cylinder or a frustum of a cone.
This baking surface is very generally heated either by a gas ramp, or electrically by incorporated resistors. On completion of baking, the product is detached from the heating surface by a scraper.
This heating surface is sometimes called a first baking device with the product requires baking on both sides. In this case the scraper causes the product to fall onto a second heating surface generally flat (rotating plate, alternating table, or an endless band) or again cylindrical.
The spreading device is very often that already used previously in drilling machines, that is to say a cylinder or an endless band dipping into a paste tank with substantially constant level. The generators of the spreader device are parallel to the generator of the baking surface which is closest to it. The spacing between said generator and that, closest, of the spreader device is substantially equal to the thickness of the product at the commencement of baking. The tangential speed of the two devices, baking surface and spreader, may be, in the vicinity of the transfer generators, in the same direction or in opposite direction.
It is rare for the desired shape of the finished product to be that of a continuous band of constant width and the means used to give the product a pre-determined shape, round, eliptical, square, in parallel strips, etc., are various.
Sometimes this shape in engraved in relief in a plurality of patterns on the heating surface, the reliefs which are successively presented before the smooth coater alone receiving a layer of paste, the "hollow" parts being spared.
The reverse is also possible and in certain machines, the heating surface is smooth and continuous and the coater includes reliefs so as to limit the pasting to the latter, but it is then necessary for the level of the paste in the tank to be adjusted precisely and very substantially constant.
In order to enable modification of the shape of the finished products by simple manipulation, it has been conceived to provide a smooth surface both for the heating surface and for the coater and to associate with a machine a "shaper" device such that at least before the transfer the pasting of the coater is limited in the corresponding shape on the heating surface to that desired for the finished product, that is to say whose development is deduced from the shape of the finished product by an orthogonal affinity (development superposable on the desired shape if the tangential speeds of the heating surface and of the coater are equal, of which development the dimensions in the direction perpendicular to the transfer generators are deduced from the corresponding dimensions of the desired shape in applying to them a coefficient equal to the ratio of the above said tangential speeds).
It is clear that to make the shape of the finished products vary, it then suffices to modify, by adjustment or by interchangeability, the shaper device which can be made easily accessible.
Known shaper devices are of two types. In the first case, the coaterdips conventionally into a paste tank and the film of paste that it draws and whose width is equal to the length of the generators of said coater, encounters at a predetermined point of its path, before arriving opposite the tansfer generator of the heating surface, either a wiper (movable scraper), or a deflector (generally cylindrical with hollow impressions) which produces on the coater the removal of the past at any point external to the contour suitable for the pellicle to transfer onto the heating surface. In a second case the coater does not dip into the container of paste but it receives the latter from a hopper which pours it along an upper generator of said coater through a slot whose length varies progressively with the passage of the coater which then draws towards the heating surface and from the origin of the pasting only the paste strictly necessary and in the appropriate shape.
The first type of shaper has the drawback of imparting an agitation to the paste (total pasting, wiping or tangential removal, or falling back into the tank) which is undesirable and does not permit the obtainng in positive manner of distinct contours for the finished product (tears and/or burrs on the edges at the moment of removal).
The second type of shaper seems better adapted to the operation to be carried out, but the aperture control of the slot is relatively complex and laborious since it necessitates a cam which drives the transmission through cables and pulleys and, in addition, the hopper system requires a rather fluid paste hence containing a fairly large amount of water which must be evaporated during baking which increases the expenditure of energy and results in blisters on the finished product although generally a smooth surface is sought.